As a parameter indicating a characteristic of a time-series signal such as a sound signal, a parameter such as LSP is known (see, for example, Non-patent literature 1).
Since LSP consists of multiple values, there may be a case where it is difficult to use LSP directly for sound classification and section estimation. For example, since the LSP consists of multiple values, it is not easy to perform a process based on a threshold for which LSP is used.
By the way, a parameter η is proposed by the inventor though it is not publicly known. This parameter η is a shape parameter that defines probability distribution to which encoding targets of arithmetic codes belong, in an encoding system for performing arithmetic encoding of quantized values of coefficients in a frequency domain, which uses, for example, such a linear prediction envelope that is used in the 3GPP EVS (Enhanced Voice Services) standard. The parameter η has relevance to distribution of the encoding targets, and it is possible to perform efficient encoding and decoding by appropriately specifying the parameter η.
Further the parameter η can be an indicator indicating a characteristic of a time-series signal. Therefore, the parameter η can be used for techniques other than the encoding process described above, for example, for voice/acoustic related techniques for sound classification, sound section estimation and the like.
Furthermore, since the parameter η consists of a single value, a process based on a threshold for which the parameter η is used is easier in comparison with a process based on a threshold for which LSP is used. Therefore, the parameter η can be easily used for sound classification and section estimation.